Pipe and bar clamps are widely used by cabinet makers and others for the purpose of clamping a workpiece or pieces together to facilitate a particular work application. For example, U.S. Pat. No. 5,064,178 discloses a conventional pipe clamp of this type, comprising an elongated pipe or beam, a tail-stop clamp assembly adapted to be selectively locked in place thereon, and a head clamp assembly also slidably mounted on the pipe for axial movement relative to the tail stop assembly. The workpiece or pieces are adapted to be clamped between opposed jaws of the tail stop and head clamp assemblies in a conventional manner.
Applicant's U.S. Pat. No. 4,921,234 discloses extenders adapted to be detachably mounted on the jaws of a standard pipe or beam clamp to substantially increase clamping depth to eight or more inches. The extenders are adapted to fit most popular three-quarter inch pipe clamps, such as the well-known Pony.RTM., Brink & Cotton.RTM., Hargrave.RTM., Craftsman.RTM., and others. The extenders are adapted to slip on and off the clamp jaws of the standard pipe clamp in seconds, and substantially increase the cost effectiveness of multiple deep-clamping applications. Further, the extenders are adapted to work over, under and through other clamps for greater project versatility.
Extenders for the pipe clamp are mounted on the clamp jaws, after the clamp jaws have been removed from the pipe. The clamp jaws with the extenders are then remounted on the pipe. However, since the clamp jaws used in standard bar clamps cannot be removed from the bar on which they are mounted, applicant was confronted with the problem of providing extenders therefor without having to modify the standard bar clamp.